1. Field
Embodiments relate to a projection display device. More particularly, embodiments relate to a projection display device that can improve luminance of an image projected and a driving method thereof.
2. Description of the Related Art
In general, a projection display device includes a first display panel for realizing a red image, a second display panel for realizing a green image, a third display panel for realizing a blue image, a combination member for combining images realized in the first to third display panels as a color image, and a projection lens system that projects the combined color image, e.g., onto a large screen.
A liquid crystal display (LCD) panel, a liquid crystal on silicon (LCOS) panel, and a digital light processing (DLP) panel may be used as display panels of the projection display device. The LCOS panel includes LCDs having liquid cells formed on a semiconductor instead of a glass substrate. The DLP panel has hundreds of thousands of digital micro-mirror device (DMD) chips each performing a switch operation more than five hundred thousands times per second, and realizing an image by controlling a reflection angle of each DMD chip.
However, since the above three types of display panels cannot emit light themselves, they need a high luminance light source and an illumination lens system for providing light emitted from the light source to a display panel. The light source includes a white light source, e.g., a high pressure mercury vapor lamp, or a light source using lasers for red, green, and blue wavelengths.
Therefore, a conventional projection display device consumes a large amount of power and generates noise due to a cooling fan used to remove heat generated by the light sources. Further, the structure of the conventional projection type display device cannot be downsized, since the illumination lens system and the projection lens system have complicated structures.
Recently, in order to overcome these drawbacks, a projection display device that uses a self-emissive display panel, e.g., an organic light emitting display panel, has been proposed. When self-emissive display panels are used, the light source and the illumination lens system can be omitted, thereby simplifying the internal structure and reducing size.
However, when used in projection display devices, the self-emissive display panels cannot provide sufficient luminance compared with display panels that use a conventional light source. Accordingly, luminance of a projected image is deteriorated.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.